1. Field of the invention
The present invention relates to an art to obtain chords or the like by analyzing playing data, more particularly to improvement of an art to obtain more precise chord data and to an automatic accompaniment device for automatic accompaniment based on the obtained chord data.
2. Prior art
In general, in automatic accompaniment devices provided in electronic musical instruments, a keyboard is divided into two parts, a left side and a right side. A player uses the left side of the keyboard for designating a chord with his left hand, and the right side thereof for playing a melody.
Since this type automatic accompaniment device enables the player to designate any desired chord, his favorite accompaniment can be performed. In the case where a complex melody is played in the right side with both hands, however, chords cannot be designated with his left hand in the left side, resulting in an impossible situation of the accompaniment playing. At the same time, if the player makes a miss-touch of the chord designation, the chord decided immediately before is held because a new chord can't be decided based on a combination of the miss-touched keys. Also, chord detection in which chord is detected based on actual playing without any chord designation has been proposed. Furthermore, Japanese patent publication hei 2-52277 discloses that a tonality of music to be played is inputted at the beginning of playing and a chord is decided based on the tonality and on one tone pitch of a melody.
In the above mentioned prior art, Japanese patent publication hei 2-52277 has the disadvantage that the decided chord is inaccurate, because the chord is decided based on only one tone pitch and the tonality.